It's Been an Interesting Week in Lake Microbegon

I was a bit alarmed Wednesday, November 10, afternoon when I discovered the water level in my MicroAquarium was alarmingly low.  Was it knocked over and spilled or just overlooked when water should have been added?  Evaporation is pretty significant and water is normally added two to three times per week.

Last week, November 3, I noticed small nematodes in the MicroAquarium.  I wasn't sure what they were but over the week they had grown pretty significantly so I could identify them as nematodes (Rainis and Russell 1996).  They were crawling along the bottom through the sediment looking for food.

Halteria sp. and Pinnularia sp. continue to be the predominant species observed.  Other organisms I continue to see include Ostracods (seed shrimp) (Rainis and Russel 1996) one or two at a time, protozoa, rotifers, and algae.

Below this entry I have attached photographs of Actinosphaerium sp. (Patterson 1996) and Pinnularia sp. (Canter-Lund and Lund 1995).  I only observed Actinosphaerium on one occasion.  What happened to them?


Citations:
Rainis KG, Russel BJ.  1996.  Guide to Microlife.  Danbury, CT:  Franklin Watts.

Patterson DJ.  1996.  Free-Living Freshwater Protozoa.  London:  Manson Publishing, Ltd.

Canter-Lund H, Lund JWG.  1995.  Freshwater Algae.  Bristol (England):  Biopress Ltd.

Actinosphaerium sp. and Pinnularia sp.

I've Got Protazoa On My Mind

Wednesday November 3, 2010 I finally identified Actinosphaerium sp., spotting two individuals, in my MicroAquarium and took a nice photograph that I plan to post next week.  In the past I have misidentified Halteria sp. as Actinosphaerium within my blog so I will edit my earlier post to reflect this new knowledge.

Actinosphaerium are much larger than Halteria and move more slowly.  They are very much less abundant also, with Halteria being one of the most predominant organisms in my MicroAquarium.  Halteria sp. makes very rapid movements making it difficult to get a close up photo because as soon as one is in focus it jumps out of the frame.  Below this post is a video I made Wednesday of a number of Halteria sp. (Patterson 1996) feeding on bacteria.  The bacteria are consuming a dead rotifer.  You can see how Halteria move in the video.

The carnivorous plant, Utricularia gibba L, has small gourd shaped traps spaced along its length.  In one of the traps I could see a seed shrimp that appeared to be alive.  The traps have some kind of fibers that let prey enter but close off the exit as kind of a flexible funnel where the outlet of the funnel expands but contracts once the prey has passed.

In one part of the MicroAquarium there appears to be a small green algae bloom.  Many individuals of a green organism that appear to be fairly immobile where arrayed in a fan shape.  I hope to identify them next week.


Citation:
Patterson DJ.  1996.  Free-Living Freshwater Protozoa.  London:  Manson Publishing, Ltd.